Third Linux system basic application

1. List the user name of all logged-on users on the system, note: The same user login multiple times, only one time can be displayed .

W.H.O. | Cut-d '-f1 | Uniq

2, remove the last login to the current system of the user's relevant information;

last-1 | Cut-d '-f1 | ID #取出最后一条登录记录 and get the user's basic information or last-1 #取出最后一个登录用户的登录信息

3. Remove the shell that the user is the most default shell on the current system;

cat/etc/passwd | Cut-d:-f7 | uniq-c | Sort | Head-1

4, the third field in the/etc/passwd the value of the largest 10 users of the information is changed to uppercase and saved to the/tmp/maxusers.txt file.

Sort-t ': '-k3n/etc/passwd | tail-10 | TR A-Z >/tmp/maxusers.txt

5, take out the IP address of the current host, hint: The result of ifconfig command is sliced;

Ifconfig | grep "\<inet\>" | Grep-v "127.0.0.1" | awk ' {print $} '

6. List the file names of all files ending with. conf in the/etc directory and convert their names to uppercase and save them to the/tmp/etc.conf file.

ls/etc/*.conf | cut-d\/-F3 | TR A-Z >/tmp/etc.conf

7. Display the total number of sub-directories or files under the/var directory;

Ls-lr/var | grep "^-" | Wc-l #文件的个数 Ls-lr/var | grep "^d" | Wc-l #文件夹的个数 let sum=$ (Ls-lr/var | grep "^d" | wc-l) +$ (Ls-lr/var | grep "^-" | wc-l); echo $sum #计算总个数

8. Remove the names of the 10 groups with the lowest value of the third field in the/etc/group file;

Sort-t ': '-k3n/etc/group | head-10 | Cut-d:-f1

9. Merge the contents of/etc/fstab and/etc/issue files into the same content and save to the/tmp/etc.test file.

Cat/etc/fstab/etc/issue >/tmp/etc.test

10. Summarize the methods used to describe the user and group management commands and complete the following links:(1) Create group distro, its GID is;

Groupadd-g distro

(2) Create user Mandriva, whose ID number is 1005, the basic group is distro;

Useradd-u 1005-g distro Mandriva

（3) Create user Mageia, whose ID number is 1100, home directory is/home/linux;

Useradd-u 1100-d '/home/linux ' Mageia

(4) to the user mageia add password, password for mageedu;

echo ' mageedu ' | passwd--stdin Mageia

(5) Delete the user Mangriva, keep their home directory;

Userdel Mangriva

(6) Create user Slackware, whose ID number is 2002, Basic Group is distro, additional group Peguin;

Groupadd Peguin useradd-u 2002-g distro-g Peguin Slackware

(7) Modify the default shell of Slackware to/BIN/TCSH.

Usermod-s '/bin/tcsh ' Slackware

(8) Add additional Group Admins for user Slackware.

Groupadd Admins usermod-ag Admins Slackware

(9) to add a password for the Slackware, and require the minimum password period of 3 days, the maximum use period of 180 days, warning for 3 days;

echo "Slackware" | passwd--stdin-n 3-x 180-w 3 Slackware

(10) Add user OpenStack, whose ID number is 3003, the base group is clouds, and the additional group is Peguin and Nova.

Groupadd clouds Groupadd nova useradd-u 3003-g clouds-g Peguin,nova OpenStack

(11) Add the system user MySQL and ask its shell to be/sbin/nologin.

Useradd-s '/sbin/nologin '-R MySQL

(12) Use the Echo command to add a password for OpenStack non-interactively.

echo "OpenStack" | passwd--stdin OpenStack

Third Linux system basic application